Composite metal structure



April 17, 1956 Filed Aug. 31. 1951 w. P. MATTHEW ET AL 2,741,828

COMPOSITE METAL STRUCTURE 3 Sheets-Sheet 1 April 17, 1956 w. P. MATTHEWa-rAL 2,741,828

COMPOSITE METAL STRUCTURE Filed Aug. 5l, 1951 5 Sheets-Sheet 2 E $5 UW lg 1 s Q /04 /af /06 /0 f =Vlllllyll1 =wll 11,1114

April 17, 1956 w. P. MATTHEW E1' Ax. 2,741,828

COMPOSITE METAL STRUCTURE Filed Aug. 5l. 1951 3 Sheets-Sheet 5*...l...."I'I.....u

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COM'POSETE METAL STRUCTURE William P. Matthew, Washington, R. I., andLyman F.

Whitney, Boston, Mass., assignors, by mesne assignments, to IsthmianMetals, Inc., a corporation of Massachusetts Application August 31,1951, Serial No. 244,584

4 Claims. (Cl. 29-191.2)

This invention relates to composite structures and more especially tostructures made of two or more metal parts which may or may not be partsof a crankshaft, joined together in accordance with the teachingdisclosed in our pending application, Ser. No. 198,614, filed December1, 1950, now abandoned, for Crankshaft and Method of Making the Same. Inthe foregoing application, connector elements are used to join theadjacent surfaces of the component parts of the structure which is to befabricated, which consist essentially of a preformed, powdered metalcompact composed of to 36 part of a low melting constituent and from 95%to 1/3 part of a high melting constituent. The high melting constituentof the elements consists of a ferrous metal and forms a shape-retaining,skeletal structure which becomes bonded to the parts by the low meltingconstituent, the latter consisting of a metal selected from the groupconsisting of copper, bronze, and copper-tin mixtures in which'thecopper predominates. The present invention involves the use of connectorelements of the foregoing kindgplaced between the adjacent parts andbonded thereto and is characterized in that at least one of thecomponent parts of a pair of adjacent component parts to be joined hasan opening therein bordered by a surface opposite which is located theother component, and that the connector element for joining the partshas a bonding portion extending into the opening, which is of such shapeas tol have intimate surface contact with a substantial area of theinternal surface of the opening and is bonded thereto.

The other component may also have an opening therein' substantially inregistry with the opening in the first component and in this case, theconnector element hasV bonding portions extending into both of theopenings of such shape as to have intimate engagement with their`internal surfaces and are bonded thereto. The opposed bordering surfacesof the component parts surrounding the openings may be spaced from eachother, in which case the connector element may have a flange-likebonding section integral therewith extending between the opposedsurfaces which is intimately bonded to the opposing surfaces.

The invention will now be described in more detail and as illustratedspecifically herein with reference to the accompanying drawings inwhich: v

Fig. 1 is a group of curves showing the way the tensile strength variesas the percentages of bronze in the iron and bronze powder mixture isvaried;

Fig. 2 is a group of curves showing the way the 'elongation varies asthe percentages of bronze in the iron and bronze powder mixture isvaried; Fig. 3 is a group of curves showing the way the density variesas the percentages of bronze in the iron and bronze powder mixture isvaried and for two diierent heating periods;

Fig. 4 is a group of curves showing tensile strength in pounds persquare inch of a given mixture of iron and powder plotted againstvarious repressing pressures;

Fig. 5 is a group of curves showing percent elongation of a givenmixture of iron and bronze plotted against various repressing pressures;

Fig. 6 is a curve showing maximum fiber stress in pounds per square inchplotted against thegnumber of cycles of rotational stress necessary tocause rupture;

Fig. 7 is a longitudinal section through a pair of hollow members joinedend to end in abutting relationship by a hollow, sleeve-like connectorelement interposed between the members;

Fig. 8 is a longitudinal section through a pair of hollow members joinedend to end with a hollow sleeve-like connector element interposedbetween the members;

Fig. 9 is a section showing a hollow member joined to a liat plate witha connector element interposed between them having a neck for engagementwithin the hollow member and a flange for engagement with the plate;

element is placed by a connector element having a neckV for engagementwith the hole and a ange for engagement with the end of the angedelement;

Fig. 11 is an elevational view longitudinally of a portion of aconventional crankshaft showing a pair of crank arms and a crank pin xedbetween the ends of the crank arms;

Fig. 12 is a somewhat enlarged view of the end portions of the crankarms and the crank pin in section to show the connector elements forjoining the crank and the crank pin in abutting relationship; y

Fig. 13 is a fragmentary portion in thevicinity of an end of the crankarm and pin showing the connector element provided with complementarylocating means;

Fig. 14 is a similar fragmentary section showing a slightly modifiedconstruction wherein the connector element is seated in a shallow recessin the crank;

Fig. 15 is a plan view of the connector element for crankshaftassemblies showing the locating means;

Fig. 16 is an elevation of the connector element shown in plan in Fig.15;

Fig. 17 is a section through an alternative form of crankshaft whereinthe crank arms and bearings or pins are formed integral;

Fig. 18 isa view taken transversely'of a crankpin looking toward a crankshowing a heater element surrounding the joint at the junction of thepin and crank; and f Fig. 19 shows an isometric view of a conventionalform of induction heater element of suitable construction to be used infusing the connector element.

The connector element is a rigid, shape-retaining body preshaped to therequired dimensions for use with the parts to be joined, as willhereinafter be described with respect to specic applications. Thee1ement,in accordance with my pending application, is made of ironpowder and powdered copper, a copper and tin mix or a prealloyed bronze,preferably the latter, by intimately mixing the powder in a conicalblender or ball mill in the proper proportions. In the mixture, thenon-ferrous metal is present in an amount of about 5% to about 2/3 ofthe total weight of mixture. Satisfactory results have been obtainedwithras little as 5% non-ferrous and as much as A non-ferrous, but arange of 10 to 30% is preferred, and in this range 20% bronze seems toafford the best results as now determined. While a -1G0 mesh powder ispreferred, powder having a higher percentage of fines may be employedwith the advantage that a somewhat stronger product may result, but withthe disadvantages that finer powders cost more and do not ow as readilyin automatic compacting machines. Bronze, having the composition of 10%tin, 90% copper is preferred and may be in the form of prealloyedpowder, or may be a mixture of tin powder with copper powder. Thenon-ferrous ing atleast as much as 2%y to. 5% total impurities 5 muchas.2% carbon canbe'usedwhen some lossi of ductility can he accepted. Theiron and bronze powders.v are.. intimately mixed togetherV with asuitable Iubricant such. as 1% stearic acid, and the mixture. is. then.poured-into a molding dieand'compressed between punches, preferably 10in automatic powder pressing equipment. Aninitial form-- ing pressure ina range to 40 tons per. square inchrbut. preferably atv approximatelytonsper square: inch, forms the powder intoa coherentbodytypefiedziotliatit.

is a mechanical, unalloyedintimate.rmixture .of iron pow? 15 der andbronze .or copper. powder, or. ironcopp,er=:and.tin powders. intheproportions. referred toa-boye... Ihefpre pressed, unalloyed, coherent.body is thenlgven'arrstsin tering at a. temperaturev in the. range 1200;to 1.90119 F.,4

preferably at approximately 1500 F. for.. one quarter'l to 20 three.hours, but preferably aboutone hour whileina protective reducingatmosphere-.such as hydrogenicrackedam. monia,.or.endotherm ic producergas which serves to driver off the lubricant, relieve thehardness whichhasrbeerrintro-l duced by the first pressing-and toform a rigid body" in2.5

which the particles of iron and bronze remainzsubstantiallyz'. unalloyedbut are neverthelesssintered together; Optionh ally the sinteredconnector is then repressedrorcoinerhinta; press at a pressure offrom.50 to.1l.00tons per square inch,

the preferred portion of the range-being...approximately 0 60. to 80tons per square inch. In; the: pressing; operation. it is preferable tokeep the bodyvunder adecreasedv pres.: sure while. itis beingejectedfrom. thedie'. Thisstepris usefulv in keepingv the bodyYuniforrrr throughout; other-V 3F approximately/ 9&0 inch thick. Oneofthe connector elements which hadbeen double pressed as above and anVwiseitmay become distorted in part.

When aconnector elementmadeupfof. the constituents referred to above isutilized between. two members to be y joined and heated to atemperature.` which.. exceeds ther melting point of the lower melting.point constituentI of the element, this constituent becomes. moltenand,alloysV 4 with other constituents of the elementfamtwithr.theiadjoiningsurfaces of the members which .are .to.be.joined". During the bonding.period'wherr the lower melting [constituent is liquid, the higher;melting constituent'` retains-` the shape of the body as a whole,forming-"arrgid,skeletal|-y like. structure whichv holdsrthe parts to bejoined Vintheir original positions. during consummation. ofthejunction-. Since. the. element. includes. amateriali.whichfnormallylis softer than the members being joined, any surface inequali ties, andresidual.spacesbetweelrthez members-andthe; ele- Y ment. are, taken, upduring .expansion thereof'by-'squeezing of the softer metal of:theel'ementzinto these irregularities-4 and spaces. Y

Upon.cooling the molten constituent solidifies, andthe;

surfaceswhich. were wettedA by the molten metal areflft;

One-third partv ferrous powder'was mixed with part, bronzepowderconsisting ofv copper; and 10% 'tin in. a conical blender' to secure'-an intimate powder mixture while mixtures' were thenl compacted at-y27tone per square inch.' The compact so formedwas then sinteredn in dry*dissociated ammonia' for one hour`at"1500" andtl'en second pressed'- at-50 tonsv per square* inch to form 'connector.4 elements. Other connectorelements were made fromzthesarne.l powder mixi by'compacting thepowderat 5 satisfactory bond therewith.

Y elements.

' 1500V F. in dry dissociated'ammona. 'IHe' connector'elements so formedwere in the shape of'a wafer-like element 84A00 inch in diameter andabout 3A0 inch thick, the double pressed elements being slightly thinnerthan the single. One of the connector elements which had been doublepressed as above and another which had been single Vpressed. andsintered as` above were placed in a furnace and subjected to heattreatment for 1/2 hourat-a temperature of approximately 2000 F. whichcorresponds to the bonding temperature used whenbonding thecomponentparts of an assembly by means of these connector When cooled after suchheat treatment the parts were found to have retained their originalshape. Since at the bonding temperature the bronze was liquid and sincethe elements after heat treatment retained their shape it is evidentthat the skeletal-like structure existed during'the period when thebronze was molten.

Example 2y One-third partV ferrous .powder was mixed with 2/35 part.

den mix at45. tons per square inch andthen sinteringthe. compactatt1500fv F. for. one hour in dry dissociated am- 'Y monia-...The'connectorf elements so formed were in. the'y shape: of.. awafer-like element. 8%00l inch in. diameter and' other-which hadbeensinglepressed and sinteredasraboveV were. placed ina furnace.andsubjected to heattreatmentf for Mr hourzat a temperature ofapproximately 2050' F:

which corresponds. to therbonding: temperature used. whenv Y bondingithecomponent parts of an assembly by Vmeans of thesezconneetor elements.When cooled Vafter suchv heaty treatment'the parts" were measured4 and.`it was found that they retainedv their original shape. Since at `thebondingv temperaturethe` copper was liquidand since. the elementsvafterc heatf. treatment retainedv their size and" shape it isV evident;that. the` skeletal-like structure existed during theperiodiwhen-thecopper was molten'. f

Instead of a. mixture.- of l/al part' ferrous powder and:2/rzpatttfcopper powder elements ofthe size and made by exact-lythe sameprocedure'as outlined above'from ain-1 intimate .mixture comprising:

1.80% ferrous powder and-20%y copper powder: 2. ferrous powder and. 5%Copper powder.

Both the single, pressed. andV double. pressed variety retained'r'thei'roriginal shape after being subjected toheat treatment for 1/2"` hour ata temperature of 'approximately 20505 l?.

In makingthe above tests to determine whether the ele-` ments wouldretain their skeletal forr'n, the. elements. onlyv were subjected to the2050FL heat treatment and no attemptwas made to. determinethel question.as to. whether the elements would bond to. abutting surfacesfto form aTests were .made in regard. to. this. question.. however, andE elementsprocessed asabovewhensubjected to the 9i.. hour heat treatment. atapproximately 2050',I F... in

v close contact with anvabuttingsurface bonded. therewith.

to form a satisfactory joint. Likewise elernentsvcorn'-l prising l"ferrous and Z copper powder bond satisfactorily to abutting surfacesunderV these conditions..

While'jelernents comprising a mixture of ferrous'and copper powder'containing less` than 5 copper'powder (for'exampl'er2%-)' made bytheprocedure outlinedVabove ret'ainedtheirskeletal shape when'treatedvsingly,v they did Y annees not form a satisfactory bond when during the1A hour 2050 F. heat treatment they were held in close contact with anabutting surface.

Where elements were made by the above procedure out of an intimatemixture comprising 75% copper powder and 25% ferrous powder they did notretain their shape when subjected to the said 2050 F. heat treatment.Since these connector elements are not shape retaining when they areused to bond together two abutting steel surfaces, the assembly does notretain its alignment and the element itself becomes very porous therebylosing strength.

All the above remarks that apply in the case of elements made from anintimate mixture of ferrous and copper powders apply in the same way andto the same extent for elements made by the same procedure from anintimate mixture of ferrous powder and bronze powder except that in thecase of these latter elements the temperature of the 1A hour heattreatment was 2000 F. instead of 2050" F. The bronze powder usedcomprised approximately 90% copper and 10% tin.

In the case of the above mentioned elements made ofV an intimate mixtureof ferrous and copper powders containing over 60% copper the aforesaid20.50 F. heat treatment was accomplished in an atmosphere comprisingabout 1% hydrogen and 99% argon, while in the case of elements made ofan intimate mixture of ferrous and bronze powders the corresponding heattreatment atmosphere consisted of dissociated ammonia gas.

Referring to the drawings, Figs. l to 6 inclusive disclose groups ofcurves plotted to show the physical properties of elements producedunder various pressures and with mixtures containing various percentagesof bronze. In all cases the higher and lower melting constituents areiron and bronze respectively. Various kinds of iron may be used but thebronze is always the same except for variations in powder particle size,the composition being 90% copper and 10% tin. The data shown in Figs. 1,2 and 3 relate to tensile strength, elongation and density respectively.Curves marked B represent test pieces made up of electrolytic iron of-100 mesh mixed with bronze of -150 mesh in the proportions indicated bythe abscissa of the coordinate axes subjected first to a pressure of 27tons per square inch, then to a sintering temperature of l500 F. in dryhydrogen for one hour, then to repressing at 90 tons per square inch,and nally to resintering at 2000 F. in dry hydrogen for l/ hour. Curvesmarked C were obtained from pieces made up of electrolytic iron of -l00mesh plus bronze of -150 mesh which was iirst pressed at 27 tons persquare inch, then sintered at 1500 F. in dry hydrogen for one hour,repressed at 90 tons per square inch, and finally resintered at 2000 F.in dry hydrogen for one minute. Curves marked D, D were obtained frompieces made up of hydrogen-reduced iron plus -150 mesh bronze which werefirst subjected to a pressure of 27 tons per square inch, then sinteredat 1500 F. for one hour in dry hydrogen, repressed at 90 tons per squareinch, and finally resintered at 2000 F. in dry hydrogen in one instanceD for two minutes and in the other D for one-half hour. The curvesmarked E were obtained from pieces made up of mixtures of electrolyticiron of -400 mesh plus bronze of -300 mesh initially pressed at 27 tonsper square inch, initially sintered at 1500 F. in dry hydrogen for onehour, finally pressed at 90 tons per square inch, and finally resinteredat 2000 F. in dry hydrogen for one minute. The curves marked G were madefrom pieces consisting of electrolytic iron of -325 mesh plus bronze of-150 mesh initially pressed at 27 tons per square inch, initiallysintered at 1500 F. in dry hydrogen for one hour, repressed at 90 tonsper square inch, and resintered at 2000 F. in dry hydrogen for twominutes.

The curves plotted as Figs. 4 and 5 show characteristics of strength,elongation and density plotted against second pressings in tons persquare inch as the abscissa. The

curves marked A were produced from pieces consisting of electrolyticiron of -100 mesh plus 20% bronze of 150 mesh, initially pressed at 27tons per square inch, initially sintered at 15 00 F. in dry hydrogen forone hour, repressed at the pressures indicated along the abscissa, andthen resintered at 2000 F. in dry hydrogen for one-half hour. The curvesidentified at F, F were taken from pieces in which a single pressing wasimparted thereto and was made up of electrolytic iron of 200 mesh plus10% (F) or 20% (F') bronze of 150 mesh, initially pressed as indicatedby the abscissa line of these curves and then sintered at 2000 F. in dryhydrogen for two minutes.

The iinal plotted curve in Fig. 6 represents a plotting of maximum fiberstrength per square inch as ordinate against the number of cyclesnecessary to cause rupture as abscissa of pieces made up of electrolyticiron of -100 mesh plus 20% bronze of 1150 mesh subjected to an initialpressing of 27 tons per square inch, an initial sintering at 1500 F. indry hydrogen for one hour, a repressing at tons per square inch, and aresintering at 2000 F. in dry hydrogen for one-half hour.

All of the data applies to double-pressed and doublesintered materialexcept that shown by the curves marked F, Figs. 4 and 5, which apply tosingle-pressed and singlesintered material. In making the aboveelements, the loose powders are mixed to secure uniformity, preferablywith a lubricant, for example 1% of powdered stearic acid.

The curves marked B and C, Figs. l and 2, together show the eiect ofchanging the resintering time from one-half hour to one minute forvarying amounts of bronze powder in the powder mixture. The piecesintered for one-half hour shows a tensile strength which increases veryrapidly with increasing amounts of bronze up to about 5% and then agradual decrease. When the resintering time is one minute, the tensilestrength increases more slowly with increasing bronze to a maximum atabout 20%, but in this case the maximum tensilestrength is lower.

Comparison of the curves marked C and E, Figs. 1 and 2, shows the effectof changing the powder particle size when the resintering time is oneminute. The curve E resulted from a piece made of -400 mesh iron with300 mesh bronze, while the curve C resulted from a mixture of mesh ironwith -150 mesh bronze. lt is to be observed that with the tine, themaximum tensile strength is higher and occurs at about 10% bronzewhereas with the coarser powder the maximum tensile strength occurs atapproximately 20% bronze. Curves D, D show that when relatively impureiron powders are used the time of iinal sintering does not affect thephysical properties of the product substantially.

Curve G, Figs. l and 2, shows the physical properties of pieces madewith very line electrolytic iron powder and 100 mesh bronze powder. Thisparticular mixture has the highest tensile strength of any of them.

The curves A, Figs. 4 and 5, differ from the curves discussed above inthat they show the physical properties plotted against variousrepressing pressures. These curves show that the physical propertiesimprove with an increasing repressing pressure and that increased finaldensities are secured. In plotting the elongation, Figs. 5 and 9, a bandrather than a single line is shown simply because the ordinance scale isextended. The width of the band indicates the expected variations inthis property from one piece to another.

Curves F and F', Figs. 4 and 5, show the variations in physicalproperties of a single-pressed piece subjected to varying pressures formixtures containing 10% bronze and 20% bronze respectively. The tensilestrength and elongation of the 10% bronze piece increase with increasingpressing pressures.

The curve marked H, Fig. 6, shows the fatigue strength of a typicaldouble-pressed piece. The abscissa represents the number of cyclesnecessary to break the extensas specimen and theY correspondingl maximumber stress-A which. is pl'otted a'svthe ordinate; In thisrtestthespeci-y menisgripp'edat one endand a bending load isV applied"` elementand its composition, specific' applications thereofwillnowl bedescribed; In.y Fig. 7 the connector element 101' is'shown in the formof a hol-lowsleeve interposed between the open ends of a pair ofvabutting hollow members 12,' such' as'lengths of pipe or'hollow'electrical' conduetors.y They connector element" is shaped underpressure in accordance withv the foregoingfdescription. connectorelement need not t tightly in the open: ends' of thev members 12. Afree-'lit isdes-irable to avoid machining the parts tocloser'tolerances. The lconnector'element should be long enough so thatthe surfacev contact of each member 12 with` the connector element isgreater than the cross-sectional area of the end of either of themembers 12. After assembling the connector element and". members, heatis appliedto causev melting of the lower melting constituent of theconnector element l with the result that expansion takes place'accompanied b'yf an' alloying of the lower melting constituent of theconnector element with the members 12. Theexpan` sion 'of the connectorelement 1): causes'` it to have inti-' mate contact with the innersurfaces of the members 12 so' as to take up any irregularities andresidual spaces which may be present vas wellr as the slight clearancebetween the same which is provided to permit' ease' of assembly, thuspromoting alloying'with the members. Such connector elements aresusceptible` of quantity pro-V duction since close 'tolerancesare'notnecessary, inexpensive, and afford means for quickly'and` simplyjoining'the abutting ends of two members to' form a jointof unusualstrength -without increasing the' outside bulk of Y the joint.'

Fig. 8 shows a modified form of th'e connector for connecting theconduits 12-12, wherein the element 10 isl provided with a peripheralange 11'for interposition between the adjacent ends of the conduits.This allows heat, developed externally to be applied directly to theconnector element.

In Fig. 9 a` hollow member 14 in the form of a sleeve isishown joined toa flat plate lby'means of a connector element 18 having a cylindricalneck-like portion 20 shaped to t into the open end of the hollow memberI4 andj to have closel surface contact with its internal surface, andaflange-like portion 22for contact'with the surface ofthe plate. Whiletheconnector element 18 is illustrated as being made hollow, it is obviousthat it could be solid.

Fig; shows a member 24 having an end ange 26 joined to a at plate 28havinga hole 3i) therein over which the' end ofthe member is disposed.To unite the parts, a' connector element 32 is employed, having a neckportion 34 adapted to enter the hole 3tl'in the plate, and aange36'adapted to be interposed between the plate and the flange-26 on themember 24.'

A.- specic application of the connector element to the manufacture ofcrankshafts' issh'own in Figs. l2 yto 19 inclusive, wherein in one formit is employed for connecting a-hollow crank pin to a crank arm withoutforming an aperture inthe cranky arm for reception of the end of thepin. A portion of a conventional ycrankshaft assembly 'is-shown in Fig.ll wherein there are main bearings 38, crank arms 40 and a crank pin 42connected between the free ends of the arms.l Thecrank pin, as shown inFig, l2, sfhollow and is joinedr at its opposite ends to the flatopposedsurfaces ofthe crank-.arm by way ofthe connector elements 44. Asillustrated herein,- each connector'element4'4'is in the form of'a-bushing having a sleeveportion 46 of such sizeA asto'tit' closelywithin the open .neck ofthe crankzpinand a flangeportion 43which Theextendsrlaterally fromr-'thene'cle portionLfor engagementwith the flat'yinner'fa'c'c otthe'acrank-'armt- T heineck pore-- tion is of sucientlength to engage-thei-inner periphe'rnl'j surface of theicran'kpinl overanV area which`r issubstantia-ll-y' greater'th'arrthecross-sectionalarea offthe end of`v the pin. Thefarea of the endfaceofthe flange48- which engages the crank arm is'Y also of considerably'larger area' than the" cross-sectionalarearof the end of the crank pini.V

Each element is-assembledt'ogether with-al crank and -p'iir by slippingthenecle portion 46'into`` the open end'of the pin and brin-gingv thep'inandrelement into abutting' en# gagemcnt with the crank armV at theproper position, clamping' the member-sin position andthensurroundingthev joint by" an inductionheater 501 such as shown in Fig. 19'. The#temperature is raised until the melting" point of the lower'melting'f'p'owder' of the' connectorY clef A. ment is' reached,whereupon ythe neck' 2'8"y expands ',in't'o'" Atthei same time analloying ofthe metal of the neck and' an'ge' j portionofthe'eelementwith the pin and crank will' take"V the end of the pinandbecomes bbndedthereto.

place. The allowable tolerances between the parts prior to assemblyis'su'chV that no special apparatusY is necesary to `fit the parts'together and yet a rigid joint of high' strength is secured.

To facilitate locati'ngjthe crank' pinA and crank it may be' desirabletof provide locating means in the form of spaced recesses 52,'Fig'. 13,in the facero'f the crank arm to which theA pin is to be'attachedand-correspondingly spaced'nubs 56 on'the exposed face oftheflange 48 as illustratedl in Figs. 1f`5v and 16.?. By positioning the.recesses` 52 con-l cent'ricallyV withrelation Yto the point'thereonY atwhich the axis of the crank pin is to be connected andthe nubs.v 56concentric to the axis-of the lneck 46, the pin may be 1 easilyassembled with the crank armA inthe propel:Y posi-V Y tion merelybyinserting, the neckof the connector ele-V mentvinto the end of the crankpin and then seatingftheA nubs inthe recesses.' The nubs not onlyfunctionas locat-v ing, means, butalso serve to someextent to strengthenthe joint between theconnector and the crank in that they provide 'amore extensive bonding surface In a-somewhatmodied form, Fig. 14', inVlieu of the recess 52, a shallow annular recess 58 is for-med in th'eface ofthe cranky concentric with the intended axis of the pin forreception of the hanged-portion 48of' the* connector element. Since theangef48 is-concentric with* the axis of theneck--of the connectorelement when-.the parts are assembled,- the=axis of thevpin will beproperly' located withrespect -to the crank arm.

The` crankshaft justA described is constructed by manu-` facturing thecrank arms, pins andl bearingsv separately' and then joiningl the pinsand'bearingsto the arm. Alter-v natively,v as shown in Fig. 17, an arm60 and parti'ofl the crankl pintor bearing may bemade integral,preferably an arm-and'. one half of a pin or bearing, *whereupon anannular connector element. 64 is interposed between the adjacent-facesof thefhalf pins or' bearings andthe partsV are'permanentlyv joined byheating the kassembly to" the melting' point of the lowermeltingVconstituent as* described heretofore.. The'annulus may haveshort neckIportions 66 which extend Va short distance into the'open ends ofthepins: to Vassistin assembling the parts' and'- alsotoV improve thebond, althoughin ysoinefcases th'e'sef may be omitted.v .Y Y

While most-any,v means may beT employed forholding? the members togetherduringthe'a'pplication of healttoy form the'joint,. alconvenient deviceis shown inrFigsf- 12; 13 and 14. This comprisesforming:a'perturesrsthirough` the crank arms concentric with` the axisof the-cr'ankpin andinserting ahollow tube-"of relatively soft metallthrough these apertures and throu'ghfth'e pin'y andthenl peening theends as shown at 72;` 'Ihis-proyides-ateml porary. connectionn which"vmay readily-"be removed? by straighteningithefpeenedrportion'72atorx'eend, v v'ithiraw#A ing the tube.' from. the' assembled pa'r-ts;V

The heating element 74 previously referred to, which may be used forforming the joint in the crankshaft assembly, is an induction heatercomprised of two arms 76 pivoted at 78 so that they may readily beplaced about the joint. The heating element is supplied with electricenergy through conventional conductors 80 which also conduct coolingfluid.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modicationsand equivalents which fall within the scope of the appended claims. Thisapplication forms a continuation-in-part of our pending application,Serial No. 36,366, led July 1, 1948.

We claim:

l. An integrated composite structure comprising a plurality of ferrousmetal components, adjacent components being joined together by aconnector element, each connector element consisting essentially of apreformed, powdered metal compact composed of to 2/3 part of a lowmelting constituent and from 95% to 1/3 part of a high meltingconstituent, the high melting constituent consisting of a ferrous metal,the lower melting constituent being a material selected from the groupconsisting of copper, bronze and copper-tin mixtures in which the copperpredominates, the high melting constituent providing a shaperetainingskeletal structure bonded to said components by said low meltingconstituent, characterized in that at least one of a pair of adjacentcomponents has an opening therein bordered by an exposed surfaceopposite which is located the other component, and that the connectorelement has a bonding portion extending into the opening, which is ofsuch shape as to have intimate surface contact with the internal surfaceof said opening.

2. An integrated composite structure according to claim 1 in which bothadjacent components have substantially registering holes therein, andthe connector element has body portions extending into said holes, saidbonding portions being of such shape as to have intimate engagement withthe internal surfaces of said holes.

3. An integrated composite structure according to claim 1 in which bothadjacent components have substantially registering holes therein, theportions of said components bordering said holes being opposed and theconnector element having bonding portions extending into said holes andhaving intimate engagement with theinternal surfaces of said holes, andanother bonding portion comprising a liange-like section intermediatethe portions engaged within the holes, the opposite sides of saidange-like section having intimate engagement with the opposed marginalsurfaces of the components bordering said holes.

4. An integrated composite structure according to claim 1 in which onecomponent has an opening therein around which is a bordering surface,and the other has a at surface arranged opposite the opening and thebordering surface, and the connector element has a cylindrical bodyportion extending into the opening into intimate engagement with theinternal surface of the opening, and an integral, radially extendingange, the opposite sides of which are in intimate surface contact withthe surface bordering the opening and the surface of the othercomponent.

References Cited in the tile of this patent UNITED STATES PATENTS1,188,485 Pruyn June 27, 1916 1,219,139 Murray Mar. 13, 1917 1,518,610Steenstrup Dec. 9, 1924 1,5 87,445 Thomson .lune l, 1926 1,896,939Calkins Feb. 7, 1933 1,921,642 Stephenson Aug. 8, 1933 2,125,324Williams Aug. 2, 1938 2,225,451 Hirth Dec. 17, 1940 2,364,109 TaylorDec. 5, 1944 2,401,483 Hensel June 4, 1946

1. AN INTEGRATED COMPOSITE STRUCTURE COMPRISING A PLURALITY OF FERROUSMETAL COMPONENTS, ADJACENT COMPONENTS BEING JOINED TOGETHER BY ACONNECTOR ELEMENT, EACH CONNECTOR ELEMENT CONSISTING ESSENTIALLY OFPERFORMED, POWDERED METAL COMPACT COMPOSED OF 5% TO 2/3 PART OF A LOWMELTING CONSTITUENT AND FROM 95% TO 1/3 PART OF A HIGH MELTINGCONSTITUENT, THE HIGH MELTING CONSTITUENT CONSISTING OF A FERROUS METAL,THE LOWER MELTING CONSTITUENT BEING A MATERIAL SELECTED FROM THE GROUPCONSISTING OF COPPER, BRONZE AND COPPER-TIN MIXTURES IN WHICH THE COPPERPREDOMINATES, THE HIGH MELTING CONSTITUENT PROVIDING A SHAPERETAININGSKELETAL STRUCTURE BONDED TO SAID COMPONENTS BY SAID LOW MELTINGCONSTITUENT CHARACTERISED IN THAT AT LEAST ONE OF A PAIR OF ADJACENTCOMPONENTS HAS AN OPENING THEREIN BORDERED BY AN EXPOSED SURFACEOPPOSITE WHICH IS LOCATED THE OTHER COMPONENT, AND THAT THE CONNECTORELEMENT HAS A BONDING PORTION EXTENDING INTO THE OPENING, WHICH IS OFSUCH SHAPE AS TO HAVE INTIMATE SURFACE CONTACT WITH THE INTERNAL SURFACEOF SAID OPENING.